Blackwing Lair: Chromaggus

(Note there are many places in BWL where chromaggus can be successfully fought. The round ramp, the staircase between supression rooms, in the gate to the octagonal room he originally stands are all viable spots. The setup follows always the same principle in is probably most easily understood in this spot)

Chromaggus is different for each instance ID. His abilities are however derived from a fixed pool. He chooses 2 afflictions (debuffs) and 2 aspects (breaths) that remain unchanged until the instance resets.

Positioning
Positioning is done as shown in the illustration, all DPS groups get a paladin for healing but are expected to bandage. Its important that the DPS-safes are all covered with dispelling for magic/curse/disease/poison. Healers in theory dont need an extra cleanser since they can handle all by themselves (druid for curse and poison, priests for disease and magic) but nevertheless a paladin at at the healer spot is a good thing. Bronze cant be dispelled.

DPS
At all times, chroma is vulnerable to a certain school of magic. He constantly changes it so we have to check for it over every now and then. Aside from exploiting the vulnerability, its also important not to overnuke so the MT can keep aggro.

Time Lapse
This requires an offtank to build aggro on Chroma. When the breath is announced, the offtank runs to his safe. After the MT gets "stunned", the offtank gets aggro and immediately runs chroma back to the tank spot where he hands over aggro to the MT again. The offtank will get a personal healer (paladin) that keeps him at full health to survive the 6 seconds time lapse. The paladin shall not build any more aggro than absolutely neccessary so Chromaggus will always go after the offtank.

Since the offtank cannot outaggro the MT healers and DPS, everyone in raid but the offtank and his paladin have to become affected by time lapse. This means: Hide for the damaging breath as usual, but stay in(get into) sight of Chromaggus for the Time Lapse breath.